嗜麦芽窄食单胞菌处理苯并[a]芘-铜复合污染过程中细胞表面特性的变化

利用嗜麦芽窄食单胞菌(Stenotrophomonas maltophilia)对BaP-Cu进行降解/吸附实验,考察菌体处理污染物过程中细胞表面特性的变化。结果表明,S.maltophilia细胞表面具有较高的疏水性。从4h到72h,不同污染体系中S.maltophilia的CSH均维持在83.3%～95.6%,之后随着时间的推移,CSH开始逐渐降低。污染物可以使S.maltophilia细胞质膜的通透性增加。TEM检测结果证实处理污染物之后,菌体质膜通透性改变,破裂并出现了'孔洞',导致细胞质外流,但是细胞壁依然维持细胞形状而没有完全裂解。处理了复合污染物的菌体,到第5d细胞严重变形,周质空间变大,细胞质外泄严重,而且原核分解并逐渐消失,细胞活性降低,并逐渐丧失对重金属的吸附能力。

不同水分胁迫条件对辽东鞍山地区灌木耐旱性的影响

以辽东鞍山地区的3种常见灌木紫丁香、连翘和榆叶梅为试验对象,研究了不同水分胁迫条件对3种灌木生长和细胞膜透性及酶活性的影响。试验结果表明,紫丁香和榆叶梅的质膜通透性在后期处理中小于连翘,而酶活性高于连翘,所以紫丁香和榆叶梅的耐旱程度高于连翘,适合当地种植。

柠檬醛抑制黄曲霉生长相关机理的研究

对经柠檬醛损伤的黄曲霉 ,采用 Irwin等人方法测定质膜通透性 ,Miller方法测定试验菌对还原糖和蛋白质吸收利用率 ,Hodge等人方法纯化质膜 [Na+,K+]- ATPase,并用 L iberg方法测定其活性 ;以琥珀酸、丙酮酸和 α-酮戊二酸为底物测定 Mt呼吸速率 ,并结合扫描电镜观察和彗星图像分析 ,发现该醛能破坏细胞壁、质膜、Mt和膜选择通透性 ,并损伤核 DNA,而引起细胞的死亡 ,揭示这种单体芳香醛抗霉是多途径的复合作用 ,为其走向粮油、食品贮藏领域提供了理论依据 .

Characteristics of water relations in seedling of Machilus yunnanensis and Cinnamomum camphora under soil drought condition

The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (Machilus yunnanensis) in Yunnan Province and the introduced tree species (Cinnamomum camphora). The leaf water potential, chlorophyll content, proline content and plasma membrane permeability for two species seedlings were measured in different soil drought conditions. The results showed that, on the 9th day of drought stress, the leaf water potential of two species decreased obviously, whereas the free proline content and plasma membrane permeability increased sharply. On the 11th day, the leaf water potential of C. camphora seedlings was lower than that of M. yunnanensis seedlings; the plasma membrane permeability in C. camphora seedling leaves increased much more than that in M. yunnanensis seedling leaves, which showed that the injury to the former by soil drought stress was more severe than that to the latter. The free proline content in M. yunnanensis seedling leaves continued to increase on the 11th day, but that in the C. camphora seedling leaves started to drop obviously, indicating that the reduction of osmotic regulation substance in C. camphora seedling leaves after the 11th day was unable to maintain the osmotic balance between the plasma system and its surroundings and the water loss occurred inevitably. Comprehensively, M. yunnanensis seedlings enhanced the drought-resistance in the course of soil drought stress by maintaining higher leaf water potential and by increasing osmotic regulation substance to promote cell plasma concentration and maintain membrane structure integrity so as to reduce water loss. The subordination function index evaluated with fuzzy mathematic theory also showed that the drought-resistant capacity of M. yunnanensis seedlings was stronger than that of C. camphora seedlings.

微囊藻毒素-LR对恶臭假单胞菌细胞活性和表面特性的影响

在恶臭假单胞菌(Pseudomonas putida)降解微囊藻毒素-LR(MC-LR)的体系中,研究了菌体细胞表面特性和活性的变化,考察了MC-LR对菌体的影响,对MC-LR的微生物毒性作用进行了初步的探索.结果表明,MC-LR可以使菌体细胞质膜通透性增加,并影响菌体离子代谢及可溶性蛋白等物质的分泌.当MC-LR质量浓度由0增大到2.0 mg·L-1时,能促进菌体分泌和释放可溶性糖及Na+、Cl-等离子.流式细胞实验检测发现,MC-LR加速了菌体细胞的死亡,且死亡率随着MC-LR质量浓度的增加而增大,2.5 mg·L-1MC-LR作用5 d,比未添加MC-LR的对照体系增加了近30%.扫描电镜观察表明,在MC-LR作用下,菌体细胞的微观形貌发生了改变,细胞褶皱加深,在2.5 mg·L-1MC-LR存在下培养5 d后,大部分细胞破裂,细胞内含物流出,细胞结构损坏严重.